Observation of Network Dynamics of Ryanodine Receptors on Skeletal Muscle Sarcoplasmic Reticulum Membranes
نویسندگان
چکیده
Rabbit muscle vesicles derived from sarcoplasmic reticulum were used as a material in studying networks of ryanodine receptors by cryo electron tomography. Three-dimensional analysis reveals the dynamical features of these networks. It was found that the connection angles were rotated along the transmembrane axis of ryanodine receptors. Majority of the connections was observed at domains 6/6 of ryanodine receptors while a small group of connections were showed at domains 9/10. The flexible rotation and connection shift seem to facilitate the extension of an annular network on the wall of the sarcoplasmic reticulum in a triad.
منابع مشابه
Role of Ryanodine Receptors in the Assembly of Calcium Release Units in Skeletal Muscle
In muscle cells, excitation-contraction (e-c) coupling is mediated by "calcium release units," junctions between the sarcoplasmic reticulum (SR) and exterior membranes. Two proteins, which face each other, are known to functionally interact in those structures: the ryanodine receptors (RyRs), or SR calcium release channels, and the dihydropyridine receptors (DHPRs), or L-type calcium channels o...
متن کاملThe effects of ryanodine on passive calcium fluxes across sarcoplasmic reticulum membranes.
Ryanodine at concentrations of 0.01-10 microM increased, while greater concentrations of 10-300 microM decreased the calcium permeability of both rabbit fast twitch skeletal muscle junctional and canine cardiac sarcoplasmic reticulum membranes. Ryanodine did not alter calcium binding by either sarcoplasmic reticulum membranes or the calcium binding protein, calsequestrin. Therefore, the effects...
متن کاملDantrolene Inhibition of Sarcoplasmic Reticulum Ca Release by Direct and Specific Action at Skeletal Muscle Ryanodine Receptors*
The skeletal muscle relaxant dantrolene inhibits the release of Ca from the sarcoplasmic reticulum during excitation-contraction coupling and suppresses the uncontrolled Ca release that underlies the skeletal muscle pharmacogenetic disorder malignant hyperthermia; however, the molecular mechanism by which dantrolene selectively affects skeletal muscle Ca regulation remains to be defined. Here w...
متن کاملActivation of the skeletal muscle ryanodine receptor by suramin and suramin analogs.
Ca2+ release from skeletal muscle sarcoplasmic reticulum is activated by adenine nucleotides and suramin. Because suramin is known to interact with ATP-binding enzymes and ATP receptors (P2-purinergic receptors), the stimulation by suramin has been postulated to occur via the adenine nucleotide-binding site of the ryanodine receptor/Ca2+-release channel. We tested this hypothesis using suramin ...
متن کاملStructure and molecular organisation of the sarcoplasmic reticulum of skeletal muscle fibers.
Activation of muscle contraction is a rapid event that is initiated by depolarization of the plasma membrane and transverse (T) tubules, which following transduction in the interior of the muscle cell, activate the release of calcium from the sarcoplasmic reticulum (SR). Pioneer studies using electron microscopy defined the organization of the sarcoplasmic reticulum and the details of the junct...
متن کامل